The world is not enough

Edward O Wilson was described by Tom Wolfe as the 'new Darwin'. Here, in an exclusive extract from his hotly anticipated new book, the world's greatest science writer considers the future - or otherwise - of life itself

The 20th century was a time of exponential scientific and technical advance, the freeing of the arts by an exuberant modernism, and the spread of democracy and human rights throughout the world. It was also a dark and savage age of world wars, genocide and totalitarian ideologies that came dangerously close to global domination. While preoccupied with all this tumult, humanity managed collaterally to decimate the natural environment and draw down the non-renewable resources of the planet with cheerful abandon. We thereby accelerated the erasure of entire ecosystems and the extinction of thousands of million-year-old species. If Earth's ability to support our growth is finite – and it is – we were mostly too busy to notice.

The 20th century was a time of exponential scientific and technical advance, the freeing of the arts by an exuberant modernism, and the spread of democracy and human rights throughout the world. It was also a dark and savage age of world wars, genocide and totalitarian ideologies that came dangerously close to global domination. While preoccupied with all this tumult, humanity managed collaterally to decimate the natural environment and draw down the non-renewable resources of the planet with cheerful abandon. We thereby accelerated the erasure of entire ecosystems and the extinction of thousands of million-year-old species. If Earth's ability to support our growth is finite – and it is – we were mostly too busy to notice.

As a new century begins, we have begun to awake from this delirium. Now, increasingly post-ideological in temper, we may be ready to settle down before we wreck the planet. It is time to sort out Earth and calculate what it will take to provide a satisfying and sustainable life for everyone into the indefinite future. The question of the century is: How best can we shift to a culture of permanence, for ourselves and for the biosphere that sustains us?

The bottom line is different from that generally assumed by our leading economists and public philosophers. They have mostly ignored the numbers that count. Consider that with the global population past six billion and on its way to eight billion or more by mid-century, per-capita fresh water and arable land are descending to levels that resource experts agree are risky. The ecological footprint – the average amount of productive land and shallow sea appropriated by each person in bits and pieces from around the world for food, water, housing, energy, transportation, commerce, and waste absorption – is about one hectare (2.5 acres) in developing nations but about 9.6 hectares (24 acres) in the United States. The footprint for the total human population is 2.1 hectares (5.2 acres). For every person in the world to reach present US levels of consumption with existing technology would require four more planet Earths. The five billion people of the developing countries may never wish to attain this level of profligacy. But in trying to achieve at least a decent standard of living, they have joined the industrial world in erasing the last of the natural environments. At the same time, Homo sapiens has become a geophysical force, the first species in the history of the planet to attain that dubious distinction. We have driven atmospheric carbon dioxide to the highest levels in at least 200,000 years, we have unbalanced the nitrogen cycle, and contributed to a global warming that will ultimately be bad news everywhere.

In short, we have entered the Century of the Environment, in which the immediate future is usefully conceived as a bottleneck. Science and technology, combined with a lack of self-understanding and a Palaeolithic obstinacy, brought us to where we are today. Now science and technology, combined with foresight and moral courage, must see us through the bottleneck and out.

"Wait! Hold on there just one minute!"

That is the voice of the cornucopian economist. Let us listen to him carefully. You can read him in the pages of The Economist, The Wall Street Journal, and myriad white papers prepared for the Competitive Enterprise Institute and other politically conservative think tanks. I will use these sources to synthesise his position, as honestly as I can, recognising the dangers of stereotyping. He will meet an ecologist, in order to have a congenial dialogue. Congenial, because it is too late in the day for combat and debating points. Let us make the honourable assumption that economist and ecologist have as a common goal the preservation of life on this beautiful planet.

The economist

"Ease up. In spite of two centuries of doomsaying, humanity is enjoying unprecedented prosperity. There are environmental problems, certainly, but they can be solved. Think of them as the detritus of progress, to be cleared away. The global economic picture is favourable. The Gross National Products (GNP) of the industrial countries continue to rise. Despite their recessions, the Asian tigers are catching up with North America and Europe. Around the world, manufacturing and the service economy are growing geometrically. Since 1950, per-capita income and meat production have risen continuously. Even though the world population has increased at an explosive 1.8 per cent each year during the same period, cereal production, the source of more than half the food calories of the poorer nations and the traditional proxy of worldwide crop yield, has more than kept pace, rising from 275kg per head in the early 1950s to 370kg by the 1980s. The forests of the developed countries are now regenerating as fast as they are being cleared, or nearly so. And while fibres are also declining steeply in most of the rest of the world – a serious problem, I grant – no global scarcities are expected in the foreseeable future. Agriforestry has been summoned to the rescue: more than 20 per cent of industrial woodfibre now comes from tree plantations.

"Social progress is running parallel to economic growth. Literacy rates are climbing, and with them the liberation and empowerment of women. Democracy, the gold standard of governance, is spreading country by country. The communication revolution powered by the computer and the internet has accelerated the globalisation of trade and the evolution of a more irenic international culture.

"For two centuries, the spectre of Malthus troubled the dreams of futurists. By rising exponentially, the doomsayers claimed, population must outstrip the limited resources of the world and bring about famine, chaos and war. On occasion this scenario did unfold locally. But that has been more the result of political mismanagement than Malthusian mathematics. Human ingenuity has always found a way to accommodate rising populations and allow most to prosper. The Green Revolution, which dramatically raised crop yields in the developing countries, is the outstanding example. It can be repeated with new technology. Why should we doubt that human entrepreneurship can keep us on an upward-turning curve?

"Genius and effort have transformed the environment to the benefit of human life. We have turned a wild and inhospitable world into a garden. Human dominance is Earth's destiny. The harmful perturbations we have caused can be moderated and reversed as we go along."

The environmentalist

"Yes, it's true that the human condition has improved dramatically in many ways. But you've painted only half the picture, and with all due respect the logic it uses is just plain dangerous. As your worldview implies, humanity has learned how to create an economy-driven paradise. Yes again – but only on an infinitely large and malleable planet. It should be obvious to you that Earth is finite and its environment increasingly brittle. No one should look to GNPs and corporate annual reports for a competent projection of the world's long-term economic future. To the information there, if we are to understand the real world, must be added the research reports of natural-resource specialists and ecological economists. They are the experts who seek an accurate balance sheet, one that includes a full accounting of the costs to the planet incurred by economic growth.

"This new breed of analyst argues that we can no longer afford to ignore the dependency of the economy and social progress on the environmental resource base. It is the content of economic growth, with natural resources factored in, that counts in the long term, not just the yield in products and currency. A country that levels its forests, drains its aquifers, and washes its topsoil downriver without measuring the cost is a country travelling blind. It faces a shaky economic future. It suffers the same delusion as the one that destroyed the whaling industry. As harvesting and processing techniques were improved, the annual catch of whales rose, and the industry flourished. But the whale populations declined in equal measure until they were depleted. Several species, including the blue whale, the largest animal species in the history of Earth, came close to extinction. Whereupon most whaling was called to a halt. Extend that argument to falling ground water, drying rivers, and shrinking per-capita arable land, and you get the picture.

"Suppose that the conventionally measured global economic output, now at about $31 trillion, were to expand at a healthy three per cent annually. By 2050, it would in theory reach $138 trillion. With only a small levelling adjustment of this income, the entire world population would be prosperous by current standards. Utopia at last, it would seem! What is the flaw in the argument? It is the environment crumbling beneath us.

"The appropriation of productive land – the ecological footprint – is already too large for Earth to sustain, and it's growing larger. A recent study building on this concept estimated that the human population exceeded Earth's sustainable capacity around 1978. By 2000, it had overshot by 1.4 times that capacity. In short, Earth has lost its ability to regenerate – unless global consumption is reduced, or global production is increased, or both."

By dramatising these two polar views of the economic future, I don't wish to imply the existence of two cultures each with a distinct ethos. All who care about the economy and environment, and that includes the vast majority, are members of the same culture. The gaze of our two debaters is fixed on different points in the space-time scale in which we all dwell. They differ in the factors they take into account in forecasting the state of the world, how far they look into the future, and how much they care about non-human life. Most economists today, and all but the most politically conservative of their public interpreters, recognise very well that the world has limits and the human population cannot afford to grow much larger. They know that humanity is destroying biodiversity. They just don't like to spend a lot of time thinking about it.

The environmentalist view is fortunately spreading. Perhaps the time has come to cease calling it the "environmentalist" view, as though it were a lobbying effort outside the mainstream of human activity, and to start calling it the real-world view. In a realistically reported and managed economy, balanced accounting will be routine. The conventional GNP will be replaced by the more comprehensive Genuine Progress Indicator (GPI), which includes estimates of environmental costs of economic activity. Already, a growing number of economists, scientists, political leaders and others have endorsed precisely this change. What, then, are the essential facts about population and the environment? From existing databases we can answer that question and see more clearly the bottleneck through which humanity and the rest of life are now passing.

On or about October 12, 1999, the world population reached six billion. It has continued to climb at an annual rate of 1.4 per cent, adding around 200,000 people each day or the equivalent of the population of a large city each week. The rate, although beginning to slow, is still basically exponential: the more people, the faster the growth. During the 20th century more people were added to the world than in all of previous history. In 1800, there had been about one billion; and in 1900, still only 1.6 billion.

The pattern of human population growth in the 20th century was more bacterial than primate. When Homo sapiens passed the six billion mark we had already exceeded by as much as a hundred times the biomass of any large animal species that ever existed on the land. We and the rest of life cannot afford another 100 years like that.

By the end of the century, some relief was in sight. In most parts of the world – North and South America, Europe, Australia, and most of Asia – people had begun gingerly to tap the brake pedal. The worldwide average number of children per woman fell from 4.3 in 1960 to 2.6 in 2000. The number required to attain zero population growth – that is, the number that balances the birth and death rates and holds the standing population size constant – is 2.1 (the extra one-tenth compensates for infant and child mortality). When the number of children per woman stays above 2.1 even slightly, the population still expands exponentially. This means that although the population climbs less and less steeply as the number approaches 2.1, humanity will still, in theory, eventually come to weigh as much as the Earth and, if given enough time, will exceed the mass of the visible universe. This fantasy is a mathematician's way of saying that anything above zero population growth can't be sustained. To breed in excess is to overload the planet. By 2000, the replacement rate in all of the countries of Western Europe had dropped below 2.1. The lead was taken by Italy, at 1.2 children per woman (so much for the power of natalist religious doctrine). Thailand also passed the magic number, as well as the non-immigrant population of the United States.

The global trend toward smaller families, if it continues, will eventually halt population growth, and afterward reverse it. It seems probable that the world population will peak in the late-21st century somewhere between nine billion and 10 billion. If population control efforts are intensified, the number can be brought closer to nine billion.

Enough slack still exists in the system to justify guarded optimism. Women given a choice and affordable contraceptive methods generally practice birth control. By 1996, about 130 countries subsidised family-planning services. More than half of all developing countries in particular also had official population policies to accompany their economic and military policies, and more than 90 per cent of the rest stated their intention to follow suit. The United States, where the idea is still virtually taboo, remained a stunning exception.

Stretched to the limit of its capacity, how many people can the planet support? A rough answer is possible, but it is a sliding one contingent on three conditions: how far into the future the planetary support is expected to last, how evenly the resources are to be distributed, and the quality of life most of humanity expects to achieve. Consider food, which economists commonly use as a proxy of carrying capacity. The current world production of grains, which provide most of humanity's calories, is about two billion tonnes annually. That is enough, in theory, to feed 10 billion east Indians, who eat primarily grains and very little meat by Western standards. But the same amount can support only about 2.5 billion Americans, who convert a large part of their grains into livestock and poultry. The ability of India and other developing countries to climb the trophic chain is problematic. If soil erosion and withdrawal of groundwater continue at their present rates until the world population reaches (and hopefully peaks) at 9 to 10 billion, shortages of food seem inevitable. There are two ways to stop short of the wall. Either the industrialised populations move down the food chain to a more vegetarian diet, or the agricultural yield of productive land worldwide is increased by more than 50 per cent.

The constraints of the biosphere are fixed. The bottleneck through which we are passing is real. It should be obvious to anyone not in a euphoric delirium that whatever humanity does or does not do, Earth's capacity to support our species is approaching the limit. We already appropriate 40 per cent of the planet's organic matter produced by green plants. If everyone agreed to become vegetarian, leaving little or nothing for livestock, the present 1.4 billion hectares of arable land (3.5 billion acres) would support about 10 billion people. If humans utilised as food all of the energy captured by plant photosynthesis on land and sea – some 40 trillion watts – the planet could support about 17 billion people. But long before that ultimate limit was approached, the planet would surely have become a hellish place to exist. There may, of course, be escape hatches. Petroleum reserves might be converted into food, until they are exhausted. Fusion energy could conceivably be used to create light, whose energy would power photosynthesis, ramp up plant growth beyond that dependent on solar energy, and hence create more food. Humanity might even consider becoming someday what the astrobiologists call a type II civilisation, and harness all the power of the sun to support human life on Earth and on colonies on other planets. Surely these are not frontiers we will wish to explore in order simply to continue our reproductive folly.

Environmentalism is still widely viewed, especially in the US, as a special-interest lobby. Its proponents, in this blinkered view, flutter their hands over pollution and threatened species, exaggerate their case, and press for industrial restraint and the protection of wild places, at the cost of economic development and jobs.

Environmentalism is something more central and vastly more important. Its essence has been defined by science in the following way. Earth, unlike the other solar planets, is not in physical equilibrium. It depends on its living shell to create the special conditions on which life is sustainable. The soil, water and atmosphere of its surface have evolved over hundreds of millions of years to their present condition by the activity of the biosphere, a stupendously complex layer of living creatures whose activities are locked together in precise but tenuous global cycles of energy and transformed organic matter. The biosphere creates our special world anew every day, every minute, and holds it in a unique, shimmering physical disequilibrium. On that disequilibrium the human species is in total thrall. When we alter the biosphere in any direction, we move the environment away from the delicate dance of biology. When we destroy ecosystems and extinguish species, we degrade the greatest heritage this planet has to offer and thereby threaten our own existence.

Humanity did not descend as angelic beings into this world. Nor are we aliens who colonised Earth. We evolved here, one among many species, across millions of years, and exist as one organic miracle linked to others. The natural environment we treat with such unnecessary ignorance and recklessness was our cradle and nursery, our school, and remains our only home. To its special conditions we are intimately adapted in every one of the bodily fibres and biochemical transactions that give us life.

That is the essence of environmentalism. It is the guiding principle of those devoted to the health of the planet. But it is not yet a general worldview, evidently not yet compelling enough to distract many people away from the primal diversions of sport, politics, religion and private wealth.

The relative indifference to the environment springs, I believe, from deep within human nature. The human brain evidently evolved to commit itself emotionally only to a small piece of geography, a limited band of kinsmen, and two or three generations into the future. To look neither far ahead nor far afield is elemental in a Darwinian sense. We are innately inclined to ignore any distant possibility not yet requiring examination. It is, people say, just good common sense. Why do they think in this short-sighted way? The reason is simple: it is a hard-wired part of our Palaeolithic heritage. For hundreds of millennia those who worked for short-term gain within a small circle of relatives and friends lived longer and left more offspring – even when their collective striving caused their chiefdoms and empires to crumble around them. The long view that might have saved their distant descendants required a vision and extended altruism instinctively difficult to marshal.

The great dilemma of environmental reasoning stems from this conflict between short-term and long-term values. To select values for the near future of one's own tribe or country is relatively easy. To select values for the distant future of the whole planet also is relatively easy – in theory at least. To combine the two visions to create a universal environmental ethic is, on the other hand, very difficult. But combine them we must, because a universal environmental ethic is the only guide by which humanity and the rest of life can be safely conducted through the bottleneck into which our species has foolishly blundered.

© Edward O Wilson 2002. Extracted from 'The Future of Life' published by Little, Brown on 4 April (£17.99 hardback)